The need to sterilize articles such as medical instruments and others for use in the agriculture and fermentation industries is well known. In recent years, many methods of vapor sterilization have been developed. While these methods offer the advantage of being generally faster than sterilization by immersion in a sterilant solution, they suffer from one major disadvantage, namely the inability to sterilize the interior of a long narrow tube in a short period of time. Thus, with regard to medical instruments such as endoscopes, the difficulty in sterilizing the lumen can often negate the general advantage of using vapor sterilization.
One way of overcoming the above disadvantage is set forth in U.S. Pat. Nos. 4,410,492 and 4,337,223. The apparatus described therein comprises a sterilizing chamber with means for introducing a sterilant gas into the chamber and circulating the gas within the chamber. Disposed within the chamber is a socket for receiving the tubular end of a medical instrument. The socket is connected to a valve and a recirculating pump and the sterilant gas is recirculated from the chamber through the lumen of the instrument. The commercial apparatus, using ethylene oxide and water as the sterilant, has had little commercial success which may be attributable to the extended sterilization times of about 3 hours for flexible endoscopes and about 2 hours for the shorter, rigid endoscopes, as well as to the toxicity problems associated with ethylene oxide sterilization. In addition, the method and apparatus described in these references cannot be used to sterilize an instrument within a sterile pack since one end of the instrument must be attached to the socket.
Thus there is a current need for an effective method to sterilize medical instruments such as endoscopes in a reasonably short period of time, preferably in one hour or less. The method and device of the present invention makes vapor sterilization of such instruments practical by delivering vapor directly to the interior of the lumen in the endoscope, whether or not it is in a sterile pack.